1. Field of the Invention
The present invention relates to a method of and apparatus for hiding the numbers inputted by a user from being displayed on the liquid crystal display (LCD) provided in a digital or key telephone.
2. Description of the Related Art
Nowadays, there are many cases where the telephone communication is established through private automatic branch exchange (PABX) or key telephone system. Although the ordinary telephone is only provided with the dialing keys for inputting phone numbers 1-9 and 0, and the function keys * and #, the digital or key telephone recently developed especially for use in the private automatic branch exchange (PABX) or key telephone system includes a liquid crystal display (LCD) and light emitting diode (LED) together with additional function keys in order to provide the user with more convenience. An example of such digital telephone is the telephone Model No. SDP380L provided by Korean Samsung Electronics Co.
When using such digital telephone provided with a liquid crystal display (LCD), the numbers or information inputted by the user are displayed on the liquid crystal display (LCD) screen. Such numbers or information can include the phone number, a number or identifying information for the automatic response system, a number or identifying information of the pager, a number or identifying information for the voice mailing system, a number or identifying information for the phone banking system, etc. In this case, there can occur many cases where the number or identifying information inputted is required to be kept secret as in phone banking.
U.S. Pat. No. 5,016,276 to Matumoto, et al. entitled Common Cyptokey Generation System And Communication System Using Common Cyptokeys, disclose a system for generating a cryptokey to be shared among entities engaged in communications, in particular one known as the key predistribution system. It is disclosed identifiers for the entities engaging in communications under a center and a center algorithm which only the center knows are generated, then secret algorithms distinct to each entity are generated on added to IC cards or other cipher generation means. It is disclosed a cipher generation means is provided for each entity. It is disclosed the identifiers of the other entity are applied to computer a cryptokey, whereby a common cryptokey is generated. Also disclosed is a system for communications using the above shared cryptokey.
U.S. Pat. No. 5,463,679 to Kai, et al. entitled Public Telephone System, disclose a public telephone system that includes public telephone sets assigned with different specific numbers and allowing speech communication using cards and a center apparatus connected to the public telephone sets through a telephone line. It is disclosed the center apparatus includes a list number forming unit for forming one list number from numbers of a plurality of invalid cards produced by illegally rewriting the cards, a registering unit for registering each formed list number in association with a series number, management number, and telephone number of each of the telephone sets, a storage unit for storing the list number and the series number, management number, and telephone number of each telephone set, all of which are registered by the registering unit, and a list number transmitting unit for calling, through the telephone line, each public telephone set corresponding to the telephone number registered in the storage unit and transmitting a list number corresponding to each telephone set. It is disclosed each public telephone set includes a controller for controlling on the basis of the list number whether speech communication is allowed in use of a card.
U.S. Pat. No. 5,583,921 to Hidaka entitled Data Transmitting/ReceivingApparatus And Data Communication System, discloses when receiving a conversion instruction from a key input section, a CPU reads character data stored in a message memory to a conversion buffer, converts the same into numeric data base on a conversion table, causes a tone signal generator to convert the same into a DTMF signal and outputs the signal to a speaker. It is disclosed when an input instruction of a registration designation and message number is received from the key input section, the CPU forms transmission data for sequentially storing the input information and the numeric data converted from character data in this order, causes to convert the same into the DTMF signal and outputs the signals. It is disclosed at the time of reception of the transmission data, the CPU identifies the content of the data, restores the numeric data into the character data based on an inverse conversion table, retrieves a message number from a TEL bank memory and registers a message into a memory area assigned to the number.
U.S. Pat. No. 5,642,365 to Murakami, et al. entitled Transmitter For Encoding Error Correction Codes And A Receiver For Decoding Error Correction Codes On A Transmission Frame, disclose error correcting coding for random errors and cell loss and a transmitter for coding error correction codes and a receiver for decoding error correction codes on a transmission frame which minimizes transmission delay. It is disclosed a buffer memory divides data symbols of a data transmission cell into blocks and stores the data blocks for each of cells to form a transmission frame. It is disclosed a check code generator carries out the error correcting coding in the unit of blocks in a direction orthogonal to the direction of transmission. It is disclosed a cell composer selects a specific cell of blocks having data symbols and generates a transmission cell. A counter appends an identifier to the top of cells in the transmission direction. It is disclosed the cell with the identifier is transmitted after being replaced with a part of the coding cells as requested.
U.S. Pat. No. 5,727,050 to Mori, et al. entitled Communication Device Having A Facsimile Module For Carrying Out Confidential Communication, disclose a communication device having a facsimile module for carrying out confidential communication regardless of the type of communication device of a caller. It is disclosed a called station number (telephone or facsimile number) detector to which a telephone set on a called side is connected is an integrated unit of the facsimile module. A CPU common to the called station number detector and the facsimile module is provided in the facsimile module. It is disclosed the CPU is connected to ROM, RAM, image memory and the like and determines from the called station number and password entered by the caller whether use of a mail box in the image memory should be permitted or not. It is disclosed if the use of the mail box is permitted, the CPU allows communication between the caller terminal and the mail box. Otherwise, normal facsimile communication is carried out.